/Engine/Plugins/Runtime/MassEntity/Source/MassEntity/Public/MassObserverManager.h
void AddObserverInstance ( const [UScriptStruct](API\Runtime\CoreUObject\UObject\UScriptStruct) & FragmentOrTagType, const [EMassObservedOperation](API\Plugins\MassEntity\EMassObservedOperation) Operation, [UMassProcessor](API\Plugins\MassEntity\UMassProcessor) & ObserverProcessor )